Author:

Keywords:

aqueous-electrolyte solutions, mica surfaces, forces, contamination, components, bilayers, liquid, Science & Technology, Physical Sciences, Technology, Electrochemistry, Materials Science, Coatings & Films, Materials Science, ELECTROLYTE-SOLUTIONS, MICA SURFACES, FORCES, CONTAMINATION, LIQUID, 0303 Macromolecular and Materials Chemistry, 0306 Physical Chemistry (incl. Structural), 0912 Materials Engineering, Energy, 3406 Physical chemistry, 4016 Materials engineering

Abstract:

We have studied the particle removal efficiency of HF-based cleaning mixtures used to clean wafer surfaces during semiconductor manufacturing. SiO2, Si3N4, and metallic oxide (Al2O3, TiO2) particles can be easily removed from silicon wafers using a HF-based clean, whereas the removal of metallic particles and especially Si and polymeric particles is much more difficult. This is explained in terms of surface hydrophobicity effects. For thermal oxide wafer substrates, a low removal efficiency is observed for the positively charged Si3N4 and Al2O3 particles. This has been explained previously by redeposition of the particles from the carry-over layer during the final rinse [R. Vos, I. Cornelissen, M. Meuris, P. Mertens, and M. Heyns, in Cleaning Technology in Semiconductor Device Manufacturing VI, J. Ruzyllo, T. Hattori, and R. E. Novak, Editors, PV 99-36, p. 461, The Electrochemical Society Proceedings Series, Pennington, NJ (1999)]. Surfactants are found to increase the removal of Si and polymeric particles from silicon substrates. This is attributed to the elimination of hydrophobic attraction forces. In addition, the surfactant is also successful in preventing the particles from redepositing during the final rinse treatment, because during the rinse, both the particle and the substrate have the same surface charge. (C) 2001 The Electrochemical Society.